Apparatus for forming pattern onto article during injection molding

ABSTRACT

In the method, after the pattern-bearing film is fed to the female mold, the distal end of the film is fixed under a lower portion of the female mold, and at the same time the film is retreated by a force from the film supply portion. Thus, this tightens up the film so that the slacks or wrinkles cannot be formed on the film. Therefore, the film can be fortunately spread around the parting surface of the female mold. In the apparatus, the film suppressing frame is pressed to the female mold through the sliding rod arranged in the female mold, in such a manner that the female mold embraces the frame. Thus, the pressing of the frame is performed by a simple structure, and the film is accurately positioned to the internal surface of the female mold. Also, the film suppressing frame is constituted to advance from and retreat to the female mold. Thus, this causes a space between the both molds and an outside standby position to be useless. A space around the apparatus can be effectively utilized.

This is a division of application Ser. No. 09/263,817 filed Mar. 8,1999, now U.S. Pat. No. 6,270,331, which in is a division of Ser. No.08/429,218 filed Apr. 25, 1995, now U.S. Pat. No. 5,925,302.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for forming a pattern onto anarticle during an injection molding thereof and an apparatus for thesame, for preventing impressions of a heating board from remaining onthe surface of the molded article or molding.

2. Description of the Related Art

Conventionally, as decorative patterning methods for three-dimensionalsolid moldings, a laminate method and a transfer printing method areknown. In the laminate method, after a film on which a pattern has beenprinted is shaped or concurrently therewith, the film is adhered to asubstrate, or while or after the film is shaped, the film is filled witha resin. On the other hand, in the transfer printing method, only apattern ink of a film on which the pattern has been printed istransferred to a molded article or molding.

As a transfer printing method, a method disclosed in Japanese PatentLaid-Open Publication Serial No. SHO 62-196113, published on Aug. 29,1987 is known. In this method, as will be described later, a heatingboard which sucks a pattern-bearing film thereon is moved into a spacebetween a male mold and a female mold which are spaced apart from eachother by a predetermined distance. Then the pattern-bearing film heatedby the heating board is vacuum sucked to the inner surface of the femalemold. Thereafter, the heating board is retreated to the outside of thespace between the male mold and the female mold. Next, the male mold andthe female mold are clamped or closed. In the cavity defined by thesemolds, a molten resin is injected to form a molded article. Thus, thepattern-bearing film is attached to the surface of the molded resinarticle.

In this method, however, when the pattern-bearing film is sucked to theheating board, air is caught between the heating board and thepattern-bearing film. This air remains as air bubbles so that thepattern-bearing film is not uniformly heated. In addition, marks orimpressions of vacuum holes defined on the heating board remain on thesurface of the final molding having the pattern-bearing film suckedthereby. Thus, the appearance of the molding is adversely affected.

To solve this problem, a method as disclosed in Japanese PatentLaid-Open Publication Serial No. HEI 5-301250 (i.e., Japanese PatentApplication Serial No. HEI 4-108271) has been proposed. In this method,a square-shaped holding flame is protruded from a peripheral edge of theheating surface of the heating board so as to contact with thepattern-bearing film, and a concave portion is formed at the inside ofthe annular holding frame. When the pattern-bearing film is located tobe opposed to the heating board in order to heating the film, theconcave portion prevents the film from direct contact with the heatingsurface of the heating board. Thus, the concave portion restrains themarks or impressions of vacuum holes from being formed on the surface ofthe final molding so that the appearance of the molding is fortunatelyaffected.

In the above method, however, while the pattern-bearing film is heatedby the heating board so as to be softened, the film is transferred intothe internal surface of the female mold so as to be positioned thereto.At this state, slacks or wrinkles are liable to be formed on the filmand the positioning of the film cannot be accurately performed by theeffect of the softened film.

SUMMARY OF THE INVENTION

The present invention is made from the above-mentioned point of view. Afirst object of the present invention is to provide a method for forminga pattern onto an article during an injection molding thereof and anapparatus for the same, in which the pattern-bearing film can betransferred to a position opposed to the internal surface of the femalemold under the condition that the slacks or wrinkles are not formed onthe film, so that the pattern-bearing film can be accurately positionedto the internal surface of the female mold.

A second object of the present invention is to provide an apparatus forforming a pattern onto an article during an injection molding thereofand an apparatus for the same, in which the heating board can be simplyand securely pressed into the female mold.

A third object of the present invention is to provide an apparatus forforming a pattern onto an article during an injection molding thereofand an apparatus for the same, in which the heating board can besecurely pressed into the parting surface of the female mold.

A fourth object of the present invention is to provide an apparatus forforming a pattern onto an article during an injection molding thereofand an apparatus for the same, in which the heating board can uniformlyheat the entire pattern-bearing film.

A fifth object of the present invention is to provide an apparatus forforming a pattern onto an article during an injection molding thereofand an apparatus for the same, in which a insulation board waiting at astandby position can prevent the pattern-bearing film or the like frombeing heated and deformed-in the standby position.

A sixth object of the present invention is to provide an apparatus forforming a pattern onto an article during an injection molding thereofand an apparatus for the same, in which the pattern-bearing film can becut by a simple structure and the cutting is lower in cost.

According to one aspect of the present invention, the first object isaccomplished by a method for forming a pattern onto an article during aninjection molding thereof, comprising the steps of: feeding apattern-bearing film to a molding position where a male mold and afemale mold are opposed; heating said pattern-bering film by a heatingboard so as to soften it, said heating board having a heating surfaceand being movable into and away from a space between said male mold andsaid female mold; transferring said pattern-bearing film to an internalsurface of said female mold so as to contact said pattern-bearing filmwith said internal surface; causing said male mold and said female moldwith said pattern-bearing film therein to approach each other to form aclosed molding cavity; and injecting a molten resin into said cavity toform a molded article to adhere said pattern-bearing film to the surfaceof said article, wherein the improvement comprises the step of: feedingthe pattern-bearing film from a film supplying section to a positionwhich is opposed to the internal surface of the female mold; fixing adistal end of the pattern-bearing film by a film fixing frame arrangedat a downstream-side of the female mold along the film feedingdirection; retreating the pattern-bearing film to the film supplyingsection so as to tighten up the pattern-bearing film; and fixing thepattern-bearing film on the parting surface of the female mold, wherebythe heating board is moved into a position where the heating surfacethereof is opposed to the pattern-bearing film fixed on the partingsurface, and then the pattern-bearing film is softened by the heatingsurface of the heating board means.

In the method, after the pattern-bearing film is fed to the female mold,the distal end of the film is fixed under a lower portion of the femalemold, and at the same time the film is retreated by a tensile force fromthe film supply portion. Thus, this tightens up the film so that theslacks or wrinkles cannot be formed on the film. Therefore, the film canbe fortunately spread around the parting surface of the female mold.

According to another aspect of the present invention, the second objectis accomplished by an apparatus for forming a pattern onto an articleduring an injection molding thereof, comprising: means for feeding apattern-bearing film to a molding position where a male mold and afemale mold are opposed; heating board means for heating saidpattern-bering film so as to soften it, said heating board means havinga heating surface and being movable into and away from a space betweensaid male mold and said female mold; means for transferring saidpattern-bearing film to an internal surface of said female mold so as tocontact said pattern-bearing film with said internal surface; means forcausing said male mold and said female mold with said pattern-bearingfilm therein to approach each other to form a closed molding cavity; andresin injecting means for injecting a molten resin into said cavity toform a molded article to adhere said pattern-bearing film to the surfaceof said article, wherein the improvement comprises: a film suppressingframe for fixing said peripheral portion of said pattern-bearing filmwhich has fed by said feed means; fitting groove means, defined on theperiphery of a parting surface of said female mold, for holding the filmsuppressing frame; and a sliding rod, slidably supported within athrough-hole formed in the female mold and extended through the partingsurface thereof, for moving the film suppressing frame so that the filmsuppressing frame is-pressed into the fitting groove means with thepattern-bearing film interposed therebetween, whereby the heating boardis moved into a position where the heating surface thereof is opposed tothe pattern-bearing film fixed on the parting surface, and then thepattern-bearing film is softened by the heating surface of the heatingboard means.

In the apparatus, the film suppressing frame is pressed to the femalemold through the sliding rod arranged in the female mold, in such amanner that the female mold embraces the frame. Thus, the pressing ofthe frame is performed by a simple structure, and the film is accuratelypositioned to the internal surface of the female mold. Also, the filmsuppressing frame is constituted to advance from and retreat to thefemale mold. Thus, this causes a space between the both molds and anoutside standby position to be useless. A space around the apparatus canbe effectively utilized.

According to the other aspect of the present invention, the third objectis accomplished by an apparatus for forming a pattern onto an articleduring an injection molding thereof, wherein the improvement comprises:a pair of holding members, arranged on both sides of the female mold,for holding the heating board means so as to be opposed to the partingsurface of the female mold, the holding members being movable along adirection connecting the male and female molds so as to press theheating board means to the female mold.

In the apparatus, the heating board is held or surrounded by the holdingmembers provided on the female mold, in such a manner that the femalemold embraces the heating board. Thus, the heating board is intenselypressed to the female mold. Even if the compressed air is blown from theheating board at the vacuum formation, the holding members prevent theheating board from being apart from or removed from the female mold. Thedriving device can be miniaturized, as compared that the heating boardis pressed into the female mold by means of a driving device disposedextremely apart from the molds.

According to the other aspect of the present invention, the fourthobject is accomplished by an apparatus for forming a pattern onto anarticle during an injection molding thereof, the improvement whereinsaid heating board means is divided into a plurality of blocks, and eachblock independently controlling the amount of the heat generated by theblock.

In the apparatus, each block independently controlling the amount of theheat generated by the block. Thus, the temperature distribution can beuniform.

According to the other aspect of the present invention, the fifth objectis accomplished by an apparatus for forming a pattern onto an articleduring an injection molding thereof, wherein the improvement comprises:insulation board means for covering the entire heating surface of theheating board means when the heating board means is waiting at a standbyposition defined apart from the space between the male and female molds.

In the apparatus, the insulation board prevents the heat radiated fromthe heating board from excessively heating the pattern-bearing filmbefore forming, the forming apparatus and so forth, whereupon thisrestrains melting, deformation, fire and so forth of the pattern-bearingfilm.

According to the other aspect of the present invention, the sixth objectis accomplished by an apparatus for forming a pattern onto an articleduring an injection molding thereof, wherein the improvement comprises:heating wire means, arranged at the upstream-side of the female moldalong the film feeding direction, for heating the pattern-bearing filmso as to cut it into a proceeding portion and a following portionthereof when the heating board means is pressed into the parting surfaceof the female mold.

In the apparatus, when the heating board is pressed into the partingsurface of the female mold, the pattern-bearing film is automaticallycut by the heating wire. In addition, it is simple in structure and islower in cost.

Also, the pattern-bearing film opposed to the parting surface of thefemale mold may be heated by the heating board in a non-contact state.Alternatively, the pattern-bearing film opposed to the parting surfaceof the female mold may be heated by the heating board in a contactstate.

These and other objects, features and advantages of the presentinvention will become more apparent in light of the following detaileddescription of best mode embodiments thereof, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view schematically showing the overall construction ofan apparatus for forming a pattern onto an article during an injectionmolding thereof according to a first embodiment of the presentinvention;

FIG. 2 is a partial cross-sectional view of the heating board shown inFIG. 1;

FIG. 3 is a front view of the heating board shown in FIG. 1;

FIG. 4 is a enlarged cross-sectional view showing the heating board andthe holding frame;

FIG. 5 is a side view showing the heating board and the film suppressingframe;

FIG. 6 is a perspective view showing the film suppressing frame;

FIG. 7 is an explanation view showing a first step of the operationaccording to the first embodiment;

FIG. 8 is an explanation view showing a step next to the step of FIG. 7;

FIG. 9 is a side view of the female mold shown in FIG. 8;

FIG. 10 is an explanation view showing a step next to the step of FIG.8;

FIG. 11 is an explanation view showing a step next to the step of FIG.10;

FIG. 12 is an explanation view showing a step next to the step of FIG.11;

FIG. 13 is an explanation view showing a step next to the step of FIG.12;

FIG. 14 is an explanation view showing a step next to the step of FIG.13;

FIG. 15 is a side view schematically showing the overall construction ofan apparatus for forming a pattern onto an article during an injectionmolding thereof according to a second embodiment of the presentinvention;

FIG. 16 is a perspective view of the female mold shown in FIG. 15;

FIG. 17 is an explanation view a first step of the operation accordingto the second embodiment;

FIG. 18 is an explanation view a second step of the operation accordingto the second embodiment;

FIG. 19 is an explanation view a third step of the operation accordingto the second embodiment;

FIG. 20 is a cross-sectional view schematically showing the overallconstruction of an apparatus for forming a pattern onto an articleduring an injection molding thereof according to a third embodiment ofthe present invention;

FIG. 21 is an explanation view a step of the operation different fromthe step shown in FIG. 20;

FIG. 22 is a perspective view of the female mold shown in FIG. 20;

FIG. 23 is a perspective view schematically showing the construction ofan apparatus for forming a pattern onto an article during an injectionmolding thereof according to a fourth embodiment of the presentinvention;

FIG. 24 is a side view of the male and female molds shown in FIG. 23;

FIG. 25 is a side view of a modification of the heating board; and

FIG. 26 is a cross-sectional view of the heating board shown in FIG. 25.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a side view schematically showing the overall construction ofan apparatus for forming a pattern onto an article during an injectionmolding thereof. A male mold 1 is fixed on a mounting board 3. The malemold 1 is opposed to a female mold 2. An injection nozzle 5 is arrangedon the male mold 1 to communicate with an injection gate 4. The femalemold 2 is fixed to a ram 7 through a movable board 6. With forward andbackward traveling operation of the ram 7, the female mold 2 advances toand retreats from the male mold 1. In addition, the female mold 2 isprovided with an air exhaust hole 8 through which air in the female mold2 is exhausted to the outside by a vacuum pump (not shown in thefigure). A fitting groove 1 a in a shape of a rectangle is formed on aparting surface of the male mold 1, and another fitting groove 2 b in ashape of a rectangle is formed on a parting surface of the female mold 2so as to be opposed to the fitting groove 1 a.

At a position spaced apart from the outer peripheries of the male mold 1and the female mold 2 by a predetermined distance, a heating board 9 isdisposed The position where the heating board 9 is disposed willhereinafter be referred to as the standby position. On the other hand,the position where the male mold 1 and the female mold 2 are opposed andthe heating board 9 is moved therebetween will hereinafter be referredto as the loading position. The heating board 9 can be laterallytravelled between the standby position and the loading position by adrive means (not shown in the figure).

A pattern-bearing film X is drawn from a roll R in a direction of anarrow shown in FIG. 1 by means of chuck devices 34 and 34 so that thefilm X is fed to a position opposed to the female mold 2, as describedin later.

FIGS. 2 and 3 show the construction of the heating board 9 in detail.

The heating board 9 has a stacked structure of a heating plate 10, aliner plate 11, a heater panel 12, and an insulation plate 13 which arestacked in this order. As described in later, the heating plate 10 heatsthe pattern-bearing film X. A holding frame 14 in a shape of a rectangleis provided on the front surface of the heating plate 10. The heatingboard 9 is mounted to a support member 15 so as to be moved by solenoids16. With the operation of the solenoids 16, the heating board 9 is movedin the direction perpendicular to-the pattern-bearing film X. Thesolenoids 16 cause the heating board 9 to advance to and retreat fromthe female mold 2.

The heating plate 10 of the board 9 is made of-a metal with high heattransfer characteristic. In the area where the heating plate 10 issurrounded by a peripheral wall 14 a of the holding frame 14, a largenumber of small air blowing holes 17 are formed in an array at intervalsof a predetermined pitch. The air blowing holes 17 pass from the frontto rear surfaces of the heating plate 10. With the heating plate 10 andthe peripheral wall 14 a of the holding frame 14, a recess 14 b isformed as also shown in FIG. 5. When a ceramic layer is formed on thefront surface of the heating plate 10, radiant heat efficiency will beimproved. The liner plate 11, which is disposed behind the heating plate10, is composed of a metal plate with a high heat transfercharacteristic. The liner plate 11 has a surface which is in contactwith the rear surface of the heating plate 10. The surface has grooves18 distributed therein through which compressed air is supplied to theair blowing holes 17. An air passageway 19 is provided at the center ofthe liner plate 11. The air passageway 19 passes through the liner plate11. The air passageway 19 also passes through the center of the heaterpanel 12 and the insulation plate 13. The air passageway 19 is open atthe rear surface of the insulation plate 13. The open portion of the airpassageway 19 is connected to an air hose 20. The air hose 20 can beconnected to either a low pressure compressor 22 or a high pressurecompressor 23 by a three-way switching valve 21.

The heater panel 12 has a number of heater wires 24. The heater wires 24are connected to a lead cable (not shown in the figure) which supplieselectricity. The insulation plate 13 serves to effectively transfer theheat generated by the heater wires 24 toward the heating plate 10.

As shown in FIG. 3 and FIG. 4 (which is an enlarged view of the portiondenoted by symbol IV in FIG. 2), a seal ring receiving groove 25 isformed along the peripheral wall 14 a of the holding frame 14. A sealring 26 is fitted in the groove 25. With the seal ring 26, air leakagecan be prevented. In addition, in the vacuum molding operation, thepattern-bearing film X can be prevented from being deviated from apredetermined position.

As shown in FIGS. 1 and 2, at the standby position of the heating board9, a film suppressing device 31 is provided in opposition thereto. Thefilm suppressing device 31 includes a square-shaped film suppressingframe 32 (shown in FIG. 6). The suppressing frame 32 operates tosuppress and hold the pattern-bearing film X in a perfectly non-contactstate. The film suppressing device 31 has a chuck device 34 and a cutterdevice 35. The chuck device 34 pulls the pattern-bearing film X to theposition between the heating board 9 and the film suppressing frame 32while the film suppressing frame 32 is apart from the heating board 9.The cutter device 35 cuts the pulled pattern-bearing film X to have apredetermined size. The cutter device 35 is driven by an air cylinder36.

The pattern-bearing film X is initially in the form of a strip on whichparticular patterns Y (see FIG. 3) are printed at predeterminedintervals. The pattern-bearing film X is wound in a roll (R) shape andheld on a supply and holding device S.

As an example of the “laminate film” for the above-mentionedpattern-bearing film, a thermoplastic resin such as acrylic resin,acrylonitrile-butadiene-styrene copolymer (ABS), or polyvinyl chloridewith a pattern printed may be used.

As an example of the above-mentioned transfer printing film, such amaterial may be used where a transfer printing layer composed of atransparent protection layer, a pattern layer, and an adhesive layer isformed over a releasable substrate film such as biaxial stretchingpolyethylene terephthalate resin or polypropylene.

From the viewpoint of the three-dimensional contour-followingcharacteristic (molding characteristic) required in the-process forinjection-molding articles with simultaneous forming of patterns andfrom the viewpoint of durability (such as wearing resistance) of thesurface of the pattern, “a resin which will become a non-tackythermoplastic solid even in a non-crosslinked state after drying of thediluting solvent” may be used. Such resin is disclosed in JapanesePatent Laid-Open Publication Serial No. SHO 61-69487 and SHO 60-161121.An example of the film substrate material of the laminate film or thetransparent protection layer of the transfer film is a substance where anon-tacky thermoplastic copolymer such as acrylic resin with a glasstransition temperature of 0 to 250° C. is added with a polymerizablecrosslinkable radical such as acryloyl radical or meta-acryloyl radical.

The substance in a state before polymerization or crosslinking istransferred or laminated to the surface of the injected resin molding.Thereafter, with radiation of ultraviolet rays or electric beam, theresultant laminate is crosslinked so that it is hardened.

Now, with reference to FIGS. 7 to 14, an operation of the apparatus willbe described. The operation starts from a state of FIG. 1, and then thechuck device 34 catches the end of the pattern-bearing film X and pullsit across the male and female molds 1 and 2 until it covers the entirecavity of the female mold 2, as shown in FIG. 7. The film suppressingframe 32 is moved from the standby position disposed outside the regionof the male mold 1 and the female mold 2 to a position opposed to thefemale mold 2 with the pattern-bearing film X therebetween as shown inFIG. 7. Thereafter, the suppressing frame 32 is adjusted to coincidewith the fitting groove 2 b on the parting surface of the female 2. Thegroove 2 b is defined so that it surrounds the cavity surface.

Next, as shown in FIG. 8, the film suppressing frame 32 is pressed intothe fitting groove 2 b with the pattern-bearing film X interposedtherebetween. Thus, the pattern-bearing film X is contacted to theparting surface of the female mold 2. At this point, it is preferredthat the outer surface of the film suppressing frame 32 is level withthe parting surface of the female mold 2 after the fitting is completed.However, as shown in the figure, when a groove 1 a for fitting the filmsuppressing frame 32 is formed on the peripheral portion of the malemold 1 so that it is opposed to the fitting groove 2 b of the femalemold 2, it is not necessary to cause the outer surface of the filmsuppressing frame 32 to be level with the parting surface. Rather, thefilm suppressing frame 32 may protrude so that a peripheral portion 14 aof the holding frame 14 can be easily pressed. FIG. 9 is a front view ofthe female mold 2 seen from the left in FIG. 8. As shown in FIG. 9, thefilm suppressing frame 32 has a connection portion 32 connected to adriving source disposed on the side thereof.

Next, as shown in FIG. 10, the heating board 9 at the standby positionis moved to the front surface of the female mold 2. Thereafter, by theperipheral wall 14 a of the holding frame 14 on the heating board 9, thepattern-bearing film X is pressed through the film suppressing frame 32.At this stage, the pattern-bearing film X is brought in contact with theperipheral wall 14 a of the holding frame 14. Thus a closed heatingspace is defined, and the pattern-bearing film X is heated in anon-contact state. After the pattern-bearing film X is satisfactorilysoftened, as shown in FIG. 11, it is subjected to a vacuum suctionthrough the air exhaust hole 8. When necessary, together with the vacuumsuction, air may be blown toward the pattern-bearing film X through theair blowing hole 17. Thus, the pattern-bearing film X is caused toaccord to the contour of the cavity surface 2 a.

Thereafter, as shown in FIG. 12, the heating board 9 is retreated to thestandby position. Next, the female mold 1 and the male mold 2 areclamped. A molten resin is injected from the injection gate 4 so thatthe cavity is filled therewith.

After the molten resin is cooled and solidified, as shown in FIG. 13,the male mold 1 and the female mold 2 are opened and then the filmsuppressing frame 32 is separated from the film suppressing framefitting groove 2 b on the female mold 2. Thus, a final resin moldingwhich is adhered to the pattern-bearing film X is taken out. When thepattern-bearing film X is a transfer printing film, only the substratefilm is peeled off with the pattern being left on the final molding.

In another example of the method of opening the mold, after the moltenresin has been cooled and solidified, as shown in FIG. 14, the filmsuppressing frame 32 is moved from the fitting groove 2 b of the femalemold 2 into the fitting groove 1 a of the male mold 1. After thepattern-bearing film X is released, the mold opening operation shown inFIG. 13 may be performed. In this method, the molding may be more easilytaken out from the male mold 1 and the female mold 2.

An effect intrinsic to the above-described embodiment is that since thepattern-bearing film X is fixed directly on the parting surface of thefemale mold and is thereafter heated and softened, deformation anddisplacement seldom take place on the pattern-bearing film X. Inparticular, when a pattern is to positionally coincide with the mold, ahigh positional accuracy is readily obtained. When the pattern isaccurately positioned on the convex and concave of the male and femalemolds, a positional mark such as a cross-shaped letter is printed inadvance on the pattern-bearing film X, it is detected by a positionalsensor such as a photoelectric tube disposed on the apparatus, and thenthe feeding of the pattern-bearing film X may be stopped depending onthe detected signal.

In the above-mentioned embodiment, the transfer printing method wasdescribed. However, it should be noted that the present invention may beapplied to the laminate method.

In addition, in the embodiments, the panel heater which radiatesnear-infrared rays was used. Besides such a heater, an electric heater(which uses Nichrome coils and directly radiates Joule's heat of surfaceresistor or the like to the pattern-bearing film), a ceramic panelheater (which radiates far-infrared rays), or dielectric heating may beused. Moreover, as an example of heat transfer to the pattern-bearingfilm, radiant of infrared rays, electromagnetic wave, or the like may bedirectly used. Furthermore, air in the closed space may be heated so asto use heat transfer thereof to the pattern-bearing film X. Of course,both methods may be used.

With reference to FIGS. 15 to 19, a second embodiment of the presentinvention will be described, and a driving structure of thepattern-bearing film X is improved in the embodiment. As shown in FIGS.15 and 16, to the film suppressing frame 32 are fixed two pairs ofsliding rods 36, 36, 36 and 36 which are extended through the femalemold 2 and the movable board 6 and are connected to a reciprocatingmechanism (not shown) disposed behind the female mold 2. A film fixingframe 38 is arranged under the parting surface of the female mold 2 soas to advance thereto and retreat therefrom as shown by the arrow inFIG. 15. The film fixing frame 38 has a plate extended in parallel tothe lower plate of the film suppressing frame 32, and the frame 38 atthe both ends thereof is provided with a pair of operating rods 39 and39 which have a distance therebetween being longer than the lateraldistance of the pattern-bearing film X. The operating rods 39 and 39 canbe moved by a reciprocating mechanism 40. On the other hand, a pair offeeding rollers 42 and 42 which can positively and reversely rotate arearranged at the downstream side of the film roll R supported on thesupply and holding device S. The feeding rollers 42 positively rotate soas to feed the pattern-bearing film X toward the female mold 2, whilereversely rotate to feed the film X toward the roll R.

In the embodiment, the female mold 2 is provided with a large number ofsmall air suction holes 8 a which are communicated with the cavity 2 aand the air exhaust hole 8 so that the air in the cavity 2 a is suckedthrough the small air suction holes 8 a and the exhaust hole 8 to theoutside. Insulation board 43 of thermal insulation material is arrangedin front of the heating board 9 and can be moved by a driving device 44.

When the feeding roller 42 shown in FIG. 15 is positively rotated andthe chuck device 34 is activated, the pattern-bearing film X is drawnuntil it covers the entire parting surface of the female mold 2, asshown in FIG. 17. The state shown in FIG. 17 corresponds with that shownin FIG. 7 of the first embodiment. Thus, the lower end of thepattern-bearing film X is moved to the inside of the film fixing frame38. In this state, however, a little excess of the pattern-bearing filmX is fed by the inertia thereof so that slacks or wrinkles are formed inthe film X, as shown in FIG. 17. Therefore, as shown in FIG. 18, thefilm fixing frame 38 is retreated by the reciprocating mechanism 40through the operating rods 39, so that the lower end of the film X isfixed by the film fixing frame 38, and at the same time the feedingroller 42 is reversely rotated. Thus, the film X is tightened so thatthe slacks or wrinkles can be removed. Thereafter, the sliding rods 36are retreated, as shown in FIG. 19, so that the film suppressing frame32 is pressed into the fitting groove 2 b with the film X interposedtherebetween. The state shown in FIG. 19 corresponds with that shown inFIG. 8 of the first embodiment.

Processes after the state shown in FIG. 19 corresponds with theprocesses shown in FIGS. 10 to 14, and a final resin molding on which apattern is formed during the injection is removed from the molds. Also,in this embodiment, the insulation board 43 is located opposite to theheating surface of the heating board 9 waiting on the standby positionshown in FIG. 15. Therefore, the insulation board 43 prevents the heatradiated from the heating board 9 from excessively heating thepattern-bearing film before forming, the forming apparatus and so forth,whereupon this restrains melting, deformation, fire and so forth of thepattern-bearing film.

Now, with reference to FIGS. 20 to 22, a third embodiment of the presentinvention will be described. FIGS. 20 and 21 are sectional views of theapparatus taken along a lateral line, respectively. As shown in FIGS. 20to 22, two pairs of members 50 for holding heating board 9 are arrangedalong the both sides of the female mold 2 and the movable board 6 so asto advance thereto and retreat therefrom. Each holding member 50 isU-shape and a pair of holding members 50 have a pair of openings opposedto each other. Each holding member 50 is reciprocated through aoperating rod 53 driven by driving device 52 such as an air cylinder.

The pattern-bearing film X is fed so as to cover the entire partingsurface of the female mold 2, and then, as shown in FIG. 20, the filmsuppressing frame 32 is pressed into the fitting groove 2 b with thefilm X interposed therebetween, that is, the film X is fixed in the samestate as shown in FIG. 8. In this state, the heating board 9 is advancedto the loading position opposed to the female mold 2, and the holdingmembers 50 are located in a advanced position shown in FIGS. 20 and 22.Thereafter, the heating board 9 is inserted into a space between a pairof holding members 50. In order to facilitate the insertion, a pair ofholding members 50 should be located apart from each other so as to holdboth ends of the heating board 9, and should have a internal distance soas to slidably accommodate the heating board 9.

In the state shown in FIG. 20, holding members 50 are advanced to theleft in FIG. 20 (a male direction ) by the driving device 52, whereuponthe heating board 9 is apart from the female mold 2. In this state, thedriving device 52 causes the operating rods 53 to move to the right ofFIG. 21, that is, a direction of the arrow shown in FIG. 21. Thus, theheating board 9 held by the holding members 50 are retreated to thefemale mold 2, and then holding frame 14 disposed in front of theheating member 9 are brought into contact with the film suppressingframe 32. When the air in the cavity 2 a is sucked through the exhausthole 8, the pattern-bearing film X which is spread around the openingsof the cavity 2 a is sucked to the internal surface thereof. This stateis shown in FIG. 21. The processes after this state corresponds with theprocesses of the first and second embodiments so that the descriptionthereof will-be omitted.

According to the third embodiment, the heating board is held orsurrounded by the holding members provided on the female mold so thatthe heating board is intensely pressed to the female mold. Even if thecompressed air is blown from the heating board at the vacuum formation,the holding members prevent the heating board from being apart from orremoved from the female mold. The driving device can be miniaturized, ascompared that the heating board is pressed into the female mold by meansof a driving device disposed extremely apart from the molds.

With reference to FIGS. 23 and 24, a fourth embodiment of the presentinvention will be described. In the embodiment, the heating board 9 isprovided at upper surface thereof with a pair of L-shaped supportingmembers 60 and 60. The distal ends of the L-shaped supporting members 60and 60 are extended toward the female mold 2, and a heating wire 62 suchas a Nichrome wire is stretched between the distal ends thereof.Therefore, as shown in FIG. 24, when the heating board 9 approaches thepattern-bearing film X sucked to the parting surface of the female mold2, the heating wire 62 comes into contact with the pattern-bearing filmX. Therefore, the film X is heated by the wire 62 and is cut into aproceeding portion and a following portion thereof. The cutting by theheating wire is much simpler in structure and lower in cost, as comparedthat the film is cut by a mechanically driven blade.

With reference to FIGS. 25 and 26, a modification of the heating boardwill be described. The heating board is divided into three pieces ofheating blocks 9A, 9B and 9C along from the upper to the lower in turn.Although it is divided into three pieces, the number of the division maybe purely optional. Electric heating wires 24A, 24B and 24C whosetemperatures are individually controlled are laid within respectiveblocks 9A, 9B and 9C, and temperature sensors 70A, 70B and 70 c arerespectively inserted into three blocks 9A, 9B and 9C.

In case the heating wire is laid within the heating board so that thetemperature of the heating board is uniformly distributed, the heatingboard constituted of one body has a tendency that the higher theposition of the heating board is, the higher the temperature thereof is,whereupon the higher the position of the pattern-bearing film to beheated is, the higher the temperature thereof is. In the modification,however, as the heating board is divided into a plurality of blocksalong the longitudinal direction and the temperatures of the respectiveblocks are individually controlled by the sensors, this prevents thetemperature of the film from ununiformly distributing. The control ofthe temperature may be depended on the prior art thereof. The decreaseand the increase of the amount of the heat generated by the wire can beperformed by the prior art controller such as a thyristor, a bimetal,etc.

Although the present invention has been shown and described with respectto best mode embodiments thereof, it should be understood by thoseskilled in the art that the foregoing and various other changes,omissions, and additions in the form and detail thereof may be madetherein without departing from the spirit and scope of the presentinvention.

1. An apparatus for forming a pattern onto an article during aninjection molding thereof, comprising: feed means that feeds apattern-bearing film to a molding position where a male mold and afemale mold are opposed; a heating board formed in a single line onlyand that heats said pattern-bearing film so as to soften it, saidheating board having a heating surface and being movable into and awayfrom a space between said male mold and said female mold; transfer meansthat transfers said pattern-bearing film to an internal surface of saidfemale mold so as to contact said pattern-bearing film with saidinternal surface; closing means that causes said male mold and saidfemale mold with said pattern-bearing film therein to approach eachother to form a closed molding cavity; and a resin injecting device thatinjects a molten resin into said cavity to form a molded article toadhere said pattern-bearing film to the surface of said article; wherein(1) said heating board is formed in a single line only and is dividedinto a plurality of heating blocks, each of said blocks independentlycontrolling heat generated by the block and having a transverse widthsufficient to cover at least most of the width of said pattern-bearingfilm, (2) said heating blocks are arranged in a vertical direction inone line only so that one heating block is disposed adjacently aboveanother heating block, and (3) said pattern-bearing film is sent from anupper position to a lower position along the vertical direction in oneline, the direction of the arrangement of the divided heating blocks andthe direction of passage of said pattern-bearing film being identical.2. The apparatus according to claim 1, wherein each of said blocksincludes therein a heating wire and a temperature sensor for detectingthe temperature of each block.